On Fri, Jul 29, 2016 at 02:16:16PM -0600, Jim Fehlig wrote: > I've noticed the behavior described by this LSN with libvirt+Xen. Config > containing <graphics type='vnc' passwd=''/> allows any client to > connect with no authentication check. I asked about this on the Xen security > list and was told that "libxl interprets an empty password in the caller's > configuration to mean that passwordless access should be permitted". The > libvirt > domXML docs are not clear on semantics of empty vnc password, only stating > "The > passwd attribute provides a VNC password in clear text". > > Should the libvirt domXML vnc passwd documentation be amended to define the > semantics of an empty string in the passwd attribute? Is the behavior > hypervisor-dependent as the documentation in qemu.conf suggests?
I guess we've never clarified the semantics in any cross-hypervisor manner. I think the fixed QEMU behaviour is the most sane from a portability POV - the Xen (and broken QEMU) behaviour was effectively overloading 2 settings onto one attribute. ie it was (ab)using a zero length password as a way to change the authentication method. We should always have distinct XML attributes for distinct settings. IOW, any toggle betweeen password and no-auth should an explicit setting and a zero length password should not magically change that. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
